The most important part of the walk-behind tractor is the drive. It is the main one of all the elements presented in the walk-behind tractor. Therefore, when there is a need to purchase a gearbox, all its further operation, and even the functionality of the walk-behind tractor, depends on the quality.
A gearbox for a walk-behind tractor is a certain type of device capable of transmitting and appropriately converting torque, for which mechanical transmissions are conductors. Accordingly, agricultural machinery will work more productively.
How to make a gearbox for a walk-behind tractor with your own hands
Two types of gearboxes, called worm gearboxes and chain gearboxes, have several small but quite important differences. They are contained in the characteristics that are inherent in the two types, but gearboxes operate with different factors: efficiency, angular speed, number of gears, as well as shafts, ratio between gears.
Gearboxes for walk-behind tractors, what are they?
When you have walk-behind tractors that are relatively cheap, they are often equipped with simplified assembly gearboxes that are not dismountable.
In this case, the service life is significantly reduced. Any additional features, including: repair, and accordingly assembly, replacement of parts, or disassembly, to check the condition of the unit.
This means that the material from which the gearbox itself is made is of very low quality. Most of the parts presented in the assembly will not be sleeved. The gearbox diagram will allow you to present not only the principle of its operation, but also determine its service life.
Expensive walk-behind tractors have gearboxes with a more complex structure and the possibility of further assembly and disassembly. Maintenance can be carried out by correcting all problems in the operation of the gearbox. Repairs must be carried out in order to extend the service life of the unit. It is important to replace faulty parts with other, more expensive elements. Lubricating the gearbox also extends its service life.
In most cases, the gearbox serves as a speed converter. That is, the angular velocity quickly and qualitatively goes to low. The input shaft will show a high angular velocity, while the output shaft will already be low.
Unforeseen breakdowns are prevented by constant and high-quality maintenance. With a stepwise variation in speed, the gearbox is called a conventional gearbox. In the case when it does not work according to a step system, it is called a variator.
Homemade bevel gear for walk-behind tractor
In principle, the gearbox does not have a very intricate structure; it is quite possible to assemble it yourself. First, make the correct calculation in rated power (Pn);Pn=Pe(hp)xFS. This will allow you to make a choice in favor correct angle, which needs to be determined for the bevel gear. According to this principle, not only the number of possible revolutions in one minute will be calculated, but also the torque will be calculated.
A self-made gearbox needs to determine its operating conditions. Among them there is radial load, or axial load, which is present on the shafts at their ends. Its operation will be optimal if the temperature and type of lubricant are selected correctly.
After completing all the above steps, you can proceed to assembly. You can choose a factory case. The diameter of the housing will tell you what kind of housing the bearings for the shaft will have. A caliper and a good quality drill will help. Next, we take two bearings under the shaft itself.
It is important to install a steel flange on the front of the gearbox. Accordingly, inside: a bearing, necessarily flanged, and a washer. The flange is attached to the generator itself using screws. The steel key, together with the drive gear and driven gear shaft, must be selected in advance. All nodes connecting to the mechanism, which is a transmission, are connected to the rotary generator. It has a pulley that provides V-belt transmission. It should be secured to the driven shaft using a nut with a spring washer.
Angular gearbox for walk-behind tractor
In the automotive industry, bevel gears are often used. Effective operation is achieved by installing such a unit.
This type of gearbox is needed to ensure coupling of the transmission with the engine itself. You can take a ready-made gearbox and simply modify it.
Basic design elements of an angular gearbox
The gearbox has several main elements, including: a flange, a housing from the generator itself, a pulley with a V-belt transmission, a steel washer, a pulley mount, a steel key, a rotor shaft, a flange mount, a flange bearing and others.
Walk-behind tractors with a gear reducer and a reduction gearbox for a walk-behind tractor
Motoblocks with modern characteristics are quite acceptable for installing a gearbox with reduction characteristics. After all, they are equipped with special air cooling.
Even heavy soil when plowing potatoes is not a problem for a machine with such a unit. You can provide quick wheel slip and other additional features.
Motoblocks with gear reduction
The gear reducer is quite simple to understand if you look at its transmission. It is a transmitter between the wheels and the engine. The direction in the walk-behind tractor changes.
The gearbox, together with the clutch, is called the transmission. It is often used in heavy walk-behind tractors.
Walk-behind tractor and reverse gearbox for it
The clutch is located strictly between bevel gears, freely located on the main shaft. This is how the reversing circuit in the gearbox is presented, which, if you look at it, is not too complicated.
It only clings to the splines in the gears. This is what allows her to change the direction of the spiral-shaped gear. The cam, or fork, is represented by the clutch itself.
A lot has been said about the benefits of a walk-behind tractor in subsidiary farming. If funds allow, they buy it. If you want to save money, make it yourself.
At first glance, this is a complex technical device that can only be made in a factory. In fact, a homemade walk-behind tractor with a gearbox from “Ant” is quite often found in the yards of home-grown farmers.
If you understand the design and have a basic locksmith kit in your home:
- welding machine;
- Bulgarian;
- drilling tool.
then you can build a self-propelled iron horse literally from scavenged materials. To do this, you need to understand how the design works.
Motoblock device. Main design elements
- Frame or stand. The engine, torque transmission system to the wheels, suspension and traction device are mounted on it. attachments;
- Power unit. Its power can be small, from 5 to 10 horsepower. Engines from mopeds, motorcycles, compressors and even chainsaws are used;
- Suspension. As a rule, primitive. Consists of homemade wheels or ready-made wheels from agricultural machinery. Sometimes automobile or motorcycle ones are used. Can be axial or portal;
- Gearbox for walk-behind tractor. One of the most important parts of the structure. Designed to reduce drive shaft speed with a simultaneous linear increase in torque. Quite often, a gearbox from a car or scooter is used as a gearbox.
However the best option There will be a homemade gearbox. It does not need to be interfaced with the power plant, since the calculation is done under specific tasks, and you are not limited to ready-made technical solution.
How to make a gearbox for a walk-behind tractor with your own hands
First you need to decide on the parameters of the power plant. IN technical specifications the number of revolutions of the crankshaft is indicated. This is the first quantity needed for calculations. This figure is not constant; when adding gas, the speed increases. Idle speed + 10% is taken as the base value.
For example, your engine idle speed + 10% is 600 rpm. The required wheel axle speed for a speed of 3 km/h is 200 rpm. Accordingly, your gearbox for a walk-behind tractor should have a gear ratio of 3:1.
Anytime garden equipment, whether it is a cultivator or a walk-behind tractor, there is a gearbox. It is the basis of the design and ensures the functioning of the equipment. A ready-made gearbox for walk-behind tractors can be purchased in a store or made independently, significantly saving the family budget.
Description
The main purpose of the device is to transmit rotation to mounted elements and wheels. It controls the direction of movement, speed and rotation. The gearbox of the MB 1 walk-behind tractor is subject to rapid wear of the belt clutch and its rupture. The “MB 2” device has the ability to mount an additional belt on the motor pulley due to the built-in reverse gear.
The new gearbox model has many positive aspects, but despite the improvements, it is not without shortcomings. A similar engine with a gearbox for a walk-behind tractor has a lower number of revolutions compared to its predecessor. Moreover, this parameter does not depend on speed and increases the time spent cultivating the land. It is also worth noting the unlocking of the wheels, which occurs when moving with the cart at second speed. Because of this, the walk-behind tractor begins to spontaneously turn to the left, which is very dangerous when driving next to traffic. Aligning the movement of equipment requires considerable skill and attentiveness.
On the outside of the gearbox there are parts that enable gear changes. When you press the gearshift lever, which has five positions, the clutch is disengaged using a fork, and then returned back. If the drive and the right axle shaft are connected, the walk-behind tractor will slow down.
Varieties
There are several main ones, which are divided according to their purpose:
- Chain ones have a metal chain in their design that ensures the rotation of the sprockets. The scheme of this option is quite simple and is complemented by a bolted connection. Among the advantages, it is worth noting ease of use, reliability and the presence of a reverse function.
- Gear-worm. They are optimally suited for engines with a vertical crankshaft. Distinctive feature is high performance and minimal noise level. Used for manufacturing various materials, including inexpensive steel and cast iron alloy.
- The belt reducer for a walk-behind tractor is similar to the chain version; the only difference is a rectangular or wedge-shaped belt used instead of a chain. The belt is secured by pulleys equipped with grooves.
- Gears can operate in an angular or straight pattern, depending on the design. The gear is mounted on shafts and can have a bevel or cylindrical shape. A similar gearbox for the Neva MB 2 walk-behind tractor is difficult to maintain, but this disadvantage is compensated by its high power, due to which it is often used in professional gardening equipment.
Service
Regular oil changes are especially important. If this rule is not followed, the additives and other ingredients included in the composition lose their properties and do not protect the parts. As a result, foaming of the composition and jamming of the gearbox is possible.
The oil level is checked using a dipstick; it should not be too low, but an excessive amount will not have the best effect on the device. The gearbox for a walk-behind tractor will last much longer when using high-quality oil, so the composition is selected in accordance with the operating conditions of the equipment.
Breakdowns
Even with timely oil changes, mechanism failures are possible, which often manifest themselves in the form of knocking. There are several main breakdowns, among which the following are worth highlighting:
- A broken chain, which is difficult to miss due to a jammed gearbox. Repair in this case consists of replacing the damaged element.
- Damage to the axle disconnection unit.
- Oil leakage indicates wear of the rubber seals.
- Changing the switching system settings. Adjustment is made by loosening the screws and engaging first gear.
- Difficulties often arise in fixing the gear; in this case, it is worth replacing the broken brushes.
What you need to know
If replacement becomes necessary constituent elements You should purchase original parts from reputable manufacturers. Most breakdowns can be fixed by anyone, but if difficulties arise, you can always turn to specialists. Also, do not forget about running-in, which will significantly increase the service life.
Today it is increasingly used for walk-behind tractors, which you can make yourself. Usually for this purpose they take improvised materials and parts taken from other equipment. This design makes it possible to operate on heavy, complex soil. It becomes indispensable when there is a lack of power in the equipment and frequent towing of wheels. The design of the gearbox is selected in accordance with the type of transmission, which consists of a gearbox, differential and clutch.
Factors that determine cost
Today in the assortment of stores you can find a suitable gearbox for the Neva walk-behind tractor for any purpose and financial capabilities. The cost is determined by the following factors:
- device characteristics;
- presence of reverse gear;
- power;
- manufacturer;
- materials used in production;
- functionality.
One of the most important elements of a walk-behind tractor is the drive. If you need to purchase a gearbox for a walk-behind tractor, then know that the service life of the entire unit will depend on its reliability. The gearbox for a walk-behind tractor, (made with your own hands), is designed to convert and transmit the torque that it receives from mechanical gears and makes agricultural machinery work.
How to make a gearbox for a walk-behind tractor with your own hands
There are differences in several important characteristics between worm and chain gearboxes for a walk-behind tractor: gear ratio, efficiency, number of shafts and gears, angular speeds and power.
What types of gearboxes are there for a walk-behind tractor?
Non-separable gearboxes are usually installed on cheap walk-behind tractors. The design of such a unit is not particularly reliable. It also has a short service life. In addition, it is impossible to carry out repairs or disassembly and assembly. In the manufacture of such units, low-quality metal and unlined parts are used. In order to understand why it is impossible long time To use a gearbox, you need to familiarize yourself with its diagram.
It is customary to install collapsible gearboxes on expensive walk-behind tractors. Thanks to this, you can disassemble the walk-behind tractor gearbox and carry out maintenance. The walk-behind tractor gearbox is repaired to increase service life, if high-quality spare parts are used when replacing faulty elements.
It is imperative to regularly diagnose the gearbox in order to repair the necessary unit in a timely manner. The gearbox should also be lubricated regularly, which will allow the unit to be used much longer.
Most often, a gearbox for a walk-behind tractor is used to convert a high angular velocity into a low one. The input shaft has a high speed and the output shaft has a low speed.
To avoid unexpected breakdowns, it is necessary to carry out regular maintenance, which will allow you to operate your agricultural machine successfully. If the angular velocity changes stepwise, the gearbox is called a gearbox, but if the change occurs steplessly, it is called a variator.
Homemade bevel gear for walk-behind tractor
You can make the walk-behind tractor yourself. To do this, you will need to calculate the rated power (Pn); Pn = Pe(hp)xFS, as a result of which the correct type of angle is determined for the bevel gear. Torque and revolutions per minute are also calculated.
You also need to determine the operating conditions of a homemade gearbox for a walk-behind tractor, which includes: radial and axial load on the ends of the shafts, minimum and maximum temperatures, determination of environmental conditions, intermittent or non-interrupted operating cycle, type of lubricant.
After determining the technical parameters, you can begin to assemble the bevel gear.
To do this, you need to select a housing for the angular gearbox.
For example, you can use the factory one, from a Ural or Dnepr motorcycle. Then, based on the diameter of the gearbox housing, we make the gear shaft bearing housing from steel. Here we use an appropriately sized drill and caliper. Then, in accordance with the planned dimensions, we select the gear shaft bearings (2 pieces).
On back side We install a steel flange for the gearbox. It will have a steel washer and a flange bearing inside. Using several screws, we attach the steel flange to the generator housing. Before this, we select the driven gear shaft, steel key and drive gear. All components are connected to the transmission mechanism and the shaft of the rotary generator. The V-belt pulley is located on the transmission mechanism and is attached to the driven pinion shaft with a nut and a spring washer.
To assemble a homemade bevel gear, you will need the following tools: calipers and ruler, straight and Phillips screwdrivers, metal drills, files and metal files, wire cutters and pliers, rubber gaskets, a vice and a hammer.
Angular gearbox for walk-behind tractor
Angular gearboxes are widely used in motorcycle equipment: in the automotive industry, modified cultivators, and industry. When installing an angular reduction gearbox on walk-behind tractors, more efficient operation is achieved under heavy loads.
This type of gearbox is usually used to connect the engine to a transmission designed for a chain. The angular gearbox for the walk-behind tractor is made from existing samples, similar ones are installed on Dnepr or Ural motorcycles. Then the gearbox will need to be modified.
Main elements of an angular gearbox
The components of the angular gearbox are: generator housing, flange bearing, rotor shaft, steel washer, steel flange, bevel drive gear, angular gear housing, steel key, pinion shaft bearings (2 pcs), driven gear shaft, steel bearing housing gear shaft, pulley mount, V-belt pulley, flange mount.
Walk-behind tractors with a gear reducer and a reduction gearbox for a walk-behind tractor
A reduction gearbox for a walk-behind tractor, in common parlance a speed reducer, is installed on modern air-cooled diesel and gasoline walk-behind tractors. Thanks to this, the user can use the walk-behind tractor on particularly heavy soils for plowing and digging up potatoes. The reduction gear helps with wheel slipping when there is not enough own power.
Motoblocks with gear reduction
To understand what a gear reducer is, let’s look at the structure of the transmission. It transmits torque from the engine to the wheels, and changes the speed and direction of movement of the walk-behind tractor. The transmission consists of a gearbox, differential, gearbox and clutch. Transmission units can be gear, chain, belt, or a combination of one or the other.
The gear transmission consists of bevel and spur gears (gear reducer). It is used on some car models and heavy walk-behind tractors. The figure shows the gear transmission of the Ugra NMB-1 walk-behind tractor, which uses a gear reducer.
Reverse gearbox for walk-behind tractor
In a reverse gearbox, reversal is performed according to the following scheme: between opposite bevel gears, which sit freely on the drive shaft, there is a coupling.
Being in extreme positions, it clings to the splines on these gears. Therefore, when the clutch engages, the direction of rotation of the gear changes. The gears must be of the helical type. The clutch drive mechanism is a traditional fork or cam.
The pride of many summer residents is a homemade walk-behind tractor, assembled with their own hands from parts that have served their age. Installing an electric motor or a small gasoline motor from an old scooter or motorcycle onto a frame with wheels is not difficult even for a novice amateur mechanic. But what you have to think about is the gearbox for the walk-behind tractor.
Walk-behind tractor design
Assembly diagrams homemade walk-behind tractors They are as varied as the parts in each owner’s garage. Dimensions are also chosen for practical reasons.
With different compositions and dimensions, there are required elements:
But the first gearbox you come across may not be suitable. You need to choose the type of structure, calculate the size of each part, so that the speed and power of movement of the mounted cultivator allows you to cultivate the land in a convenient mode - neither quickly nor slowly.
Types of gear units
Broadcast rotational movement from the motor shaft to the actuator shaft can be done by direct connection of the axes, if the speed and power of rotation of the engine are acceptable for operation, and the axes of the drive and driven shafts coincide. Such cases are extremely rare, and with several attachments for different purposes, direct transmission absolutely cannot be used. To match the speed and power of the drive and driven shafts, 4 types of mechanisms and their combinations are used. Main types of gears:
- belt;
- chain;
- gear;
- worm
The worm gear is structurally limited by the speed-reducing function; the rest can be used in both downshifts and overdrives. In addition, such a gearbox always has a driven axis perpendicular to the drive shaft. This scheme is called an angular gearbox. Except worm gear, the direction of the axis can be changed using a spatial planetary mechanism. Belt and chain drives keep the driven axis parallel to the engine axis. IN simple devices Reverse is only possible when the engine rotation changes.
Motoblocks use engines with a high number of revolutions per minute, which can be verified in the product data sheet. This means that you need to make a gearbox with your own hands to reduce the speed, and it is better to choose what type of homemade gearbox for a walk-behind tractor, knowing the characteristics of each type.
Belting
The pulley or belt that transmits rotation from shaft to shaft is familiar to every motorist who has looked under the hood of the engine compartment. The rotation speed reduction coefficient is determined by dividing the radius of the small driven wheel by the radius of the large driving wheel.
The advantages of belt gearboxes are their ease of manufacture and repair, and a wide variety of parts. And the disadvantages of the belt:
- belt stretching, decreased adhesion to the pulley due to temperature and wear;
- slippage during sudden increases in torque;
- short service life.
The shortcomings are compensated by using a spring-loaded roller that presses on the surface of the belt between the wheels, and by using a toothed belt on pulleys with transverse chamfers. Belt gearboxes require the drive and driven pulleys to be in the same plane; bending or twisting the belt will quickly lead to it breaking.
Chain type
The operating principle of a chain drive is similar to a belt drive, but sprockets are installed instead of pulleys, and the belt is replaced by a chain. Such a homemade gearbox will not allow slipping, and under similar conditions it will work much longer.
Just like a belt, chain gearbox must have a driving and driven sprocket in the same plane, and its gear ratio is calculated by the ratio of their teeth. The weight of this design is greater than that of a belt design, but it is safer to install it on powerful walk-behind tractors.
Unlike a belt drive, a chain drive requires caution or additional protective measures. If a rotating attachment collides with a thick root in the soil, its drag force will be transferred to the motor, possibly damaging it. Until the engine fails or switches off, it will try to rotate with maximum power along with the frame around the driven axis of the gearbox. The greater the engine power, the stronger the tipping torque will be.
The gear ratio of a chain gearbox can be higher than that of a belt gearbox of the same size, since the drive sprocket, even with small size, will not allow the chain to slip.
In terms of cost, ease of assembly, and prevalence of parts, a chain drive is not inferior to a belt drive.
Using gears
A walk-behind tractor with a gear reducer is more reliable, more durable than with a chain or belt. Gear structures are installed on factory products, and not only on walk-behind tractors. The units are small in size as a result of combining two gears with different diameters on one axis. For a walk-behind tractor, for example, a gearbox from an Ant scooter is perfect. But you can make your own using gears from motor vehicle gearboxes.
The required gear ratio can be provided by a planetary mechanism, in which satellite gears are installed between the outer and sun gears, mounted on a fixed ring - the carrier:
For a reduction gearbox, the sun gear is mounted on the drive shaft. The planetary gear carrier is mounted on a stationary housing, and the outer gear is connected to the actuator, rotating in the direction opposite to the sun gear.
The gear ratio of such a gearbox can be calculated as the ratio of the number of teeth on the sun gear to the number of teeth on the external gear.
To change the direction of the axis of rotation in gearboxes, a spatial planetary mechanism, in which the gears to change direction by 90 degrees must be tapered at 45 degrees each. The diameter of the gears can be different, which can be used to change the gear ratio.
For a walk-behind tractor, such an angular gearbox is rarely made with your own hands, since planetary gears the right size I still have to look. Changing the axis of rotation is often done using ready-made factory gearboxes or a worm pair.
Worm gear
To change the direction of the rotation axis perpendicularly and create a large gear ratio, contact of a flat gear with an Archimedean screw is used.
Transmission of rotation from the actuator to the motor is not possible. This is a unique feature of the worm gear; other types of gears do not have this property. The output rotation speed can be reduced by as many times as the number of teeth the gear has. This transmission is characterized by ease of assembly, high friction, small size, very popular.
In order to make a worm gearbox with your own hands, you need to select a gear with a number of teeth equal to the reduction in rotation speed in times, as well as with a pitch between the teeth equal to the pitch of the worm flange.
Reversing mechanism
The presence of a reversible transmission mechanism simplifies work in the fields, but an amateur can only do reverse at home with an electric motor. The difficulties lie in the inclusion of an additional transmission element in the circuit with the possibility of its precise movement and reliable fixation. To do this, you will need to break the existing connection with the engine, and insert into the gap new element, be it another pulley with a belt, a sprocket with a chain, or a gear. Such restoration conversions require parts manufactured with the precision of professional machines.
In this case, it is more practical to install a factory reversible gearbox. For example, from a car with a manual transmission.
DIY gearbox assembly
The operation of walk-behind tractors, and with them gearboxes, means dust, off-road conditions, heat when plowing or cold when clearing snow, uneven loads. You can extend the life of the transmission mechanism by using a closed housing.
ST-40 steel is used for the base on which pulleys, gears, and other parts are mounted. The lid can be made from less durable steel, if torque transmission elements are not attached to it.
The use of bearings for installing shafts, pulleys, sprockets, gears is mandatory, otherwise friction will dampen the rotational force, and the unit will either quickly fail or not work immediately.
Any rotating mechanism requires lubrication. Worm gearbox especially. Frequent replacement of lubricant will help extend the life of the device, for which the gearbox cover must be openable.
Gasoline, diesel engines have fuel supply adjustment and engine rotation speed. It is optimal to move the so-called gas handle to the handle of the walk-behind tractor.
When all the necessary parts have been found, plumbing tools will be required to assemble the walk-behind tractor. Can't do without welding machine, grinders, drills, metal drills.
The time spent on making a walk-behind tractor will pay for itself completely in the first summer season.
